Determination of the cutoff point of milk progesterone and use it as an early indicator of pregnancy or screening of open cows in dairy farms

الملخص EN

The present study was carried on a herd of Friesian cows during the period from June 2010 to May 2011, This herd Belongs to EL-Salhya Company for Investment and Development (Dairy cattle breeding farm number 2), which is located in El-Salhya City- Sharkia Province.

This study aimed to Calculate the optimum cutoff value of milk progesterone (P4) concentration to predict pregnancy status 19-24 days after insemination compared with diagnosis by rectal palpation performed 45-60 days of insemination and considered as the ‘‘gold standard’’ using a Receiver Operating Characteristic (ROC) analysis and analyze the sensitivity (Sense), specificity (Spes), positive predictive value (PPV) and negative predictive value (NPV) of the tests with examination of the differences in these values as the cutoff values were allowed to change.

The cutoff point obtained by ROC curve in ELISA milk test was > 6.2 ng /ml with an area under the ROC curve (AUC) of 0.890, a result referred to as ‘‘moderately accurate’’, the sensitivity % of ELISA milk test was 82.8, specificity % was 92, the negative predictive value % was 82, the positive predictive value % was 92.3.

It may be concluded that ELISA milk progesterone tests can be used as an early indicator of pregnancy and non-pregnancy in cows but with some precautions.